Cycloaliphatic acrylate compositions

ABSTRACT

Cycloalphatic acrylate compositions and methods of making them are disclosed. The compositions are mixtures containing dicyclopentadiene (meth) acrylate and (meth) acrylates such as the mono and di (meth) acrylates of tri, and tetracyclopentadiene and a mixture of the copolymers of (meth) acrylic acid with adducts of cyclopentadiene with isoprene and/or piperylene and a mixture of poly (meth) acrylates having the repeating unit ##STR1## where R 1  is hydrogen or ##STR2## R 2  is CH 2  ═CZ--C(O)--O--  Z is H, or methyl 
     n is 0, 1 or 2 and 
     m is 0 or 1 and when m is 0 there is a double bond present. 
     The compositions are useful to make cross-linkable blends with unsaturated resins or monomers and to make laminates.

This application is a divisional application of Ser. No. 951,416, filedOct. 13, 1978, U.S. Pat. No. 4,319,009, March 9, 1982 which is acontinuation-in-part of Ser. No. 866,679, filed Jan. 3, 1978, nowabandoned.

BACKGROUND OF THE INVENTION

This invention relates to a cycloaliphatic acrylate compositioncontaining mixtures of dicyclopentadiene (meth) acrylate, acrylateswhich comprise the mono and di (meth) acrylates of tri, andtetracyclopentadiene, copolymers of acrylic acid or methacrylic acidwith adducts of cyclopentadiene with isoprene and/or piperylene, and amixture of polyacrylates having the repeating unit ##STR3## Where R¹ ishydrogen or ##STR4## R² is CH₂ ═CZ--C(O)--O-- Z is H, or methyl

n is 0, 1 or 2

m is 0 or 1 and when m is 0 there is a double bond present.

The invention also encompasses thermosetting resin compositionscontaining the acrylate composition.

Dicyclopentadiene acrylate (DCPDA) is known from U.S. Pat. No. 2,414,089dated Jan. 14, 1947.

It is known from British Pat. No. 1,114,585; Modern Plastics, September1976, pages 95-103; Rubber World, June 1974, page 42 and German Pat. No.1,234,027 that a distilled or a substantially pure dicyclopentadieneacrylate can be used alone or blended with other unsaturated monomers tomake thermoplastic polymers, rubbers, or for crosslinking unsaturatedpolyesters.

The use of distilled dicyclopentadiene alkenoate concentrate to cure orcrosslink vinyl ester resins and polyester resins is known from Ser. No.814,358 and Ser. No. 814,359 both filed on July 11, 1977.

According to U.S. Pat. No. 2,414,089 (49), DCPDA can be prepared byesterification of dicyclopentadienyl alcohol or dicyclopentadiene(DCPD), or by ester exchange. Recovery of pure DCPDA is accomplished bydilution of the crude reaction mixture to reduce viscosity and density,washing with basic solutions and water, removal of diluent anddistillation under high vacuum. In Brit. Pat. No. 1,114,585 (68) andU.S. Pat. No. 3,427,363 (60) specific examples are given for thepreparation of pure DCPDA. The yield of DCPDA based on DCPD does notexceed 86.6%. German Pat. No. 1,954,548 (71) addresses itself to solvinga specific problem of the general process, namely the elimination ofemulsion formation during work-up.

While DCPDA has been known for over 30 years, no significant commercialuse has developed because the cost of production has been prohibitivefor most uses. The reason for the high cost is the requirement for adistilled product free of difunctional compounds and polymers forthermoplastic polymer applications and for a low-colored product forthermoset uses. Distillation of DCPDA is difficult because of the highreactivity of the acyrlate bond and the propensity to crosslink of thecyclopentene double bond, and because of the high boiling point of 280°C./760 MM Hg or 100° C./1.7 MM Hg. Even with well inhibited systems,distillations are limited to about 120° C. Furthermore, the polymersformed during the process and during distillation are difficult tohandle because they are partially crosslinked or gelled.

SUMMARY OF THE INVENTION

The cycloaliphatic acrylate composition of this invention comprises

(A) about 60 to 95 percent by weight of dicyclopentadiene acrylate,methacylate, or mixtures thereof,

(B) about 2 to 15 percent by weight of a mixture of polycyclopentadienylacrylates of the formula ##STR5## where R is CH₂ ═CZC(O)--O--

Z is H, or methyl

n is 1, or 2

m is 0 or 1 and when m is 0 there is a double bond present

(C) about 1 to about 21 percent by weight of a mixture of the copolymersof methacrylic acid or acrylic acid with adducts of cyclopentadiene withisoprene, piperylene, or mixtures thereof,

(D) about 0.05 to about 10 percent by weight of a mixture ofpolyacrylates having the repeating unit ##STR6## where R¹ is hydrogen or##STR7## R² is CH₂ ═CZ--C(O)--O Z is H, or methyl,

n is 0, 1, or 2, and

m is 0, or 1 and when m is 0 there is a double bond present.

Preferably the range of dicyclopentadiene (meth) acrylate is from 71 to91 percent by weight.

Preferably, the acrylate mixture range is from 9 to 12 percent byweight.

Preferably, the copolymer range is from 5 to 15 percent by weight whilethe polyacrylate range is from 0.1 to 2 percent by weight.

There are also residual or trace amounts of unreacted monomericcomponents in the composition such as about 0.2 percent by weight ofDCPD and 0-2 percent by weight of acrylic acid or methacrylic acid.

The compositions of this invention are useful to crosslink unsaturatedresins. The compositions are easy to produce with high conversion of theraw materials. They do not require purification by distillation and areequal to or superior in performance as compared to distilled DCPDA.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The reactants used to make the compositions of this invention areacrylic or methacrylic acid, and dicyclopentadiene (DCPD). DCPD can beused in the form of the pure compound or as a DCPD concentratecontaining DCPD and 2-30% of the codimers (Diels-Alder adduct) ofcyclopentadiene with isoprene, piperylene, or methylcyclopentadiene.Light and heavy components in the concentrate such as C₅ olefins, C₅diolefins, C₅ paraffins, tricyclopentadiene and dicyclopentadiene arepreferably kept below 2%, although the light components such as the C₅hydrocarbons can be as high as 7-10%.

The compositions of this invention can be prepared in stainless steelequipment by the addition of inhibited DCPD to inhibited acrylic acid(AA) or methacrylic acid (MAA) containing BF₃ catalyst. The reactiontemperature is controlled to less than 70° C. and 0.1 to 4.0 molarexcess of AA is used. Formation of emulsions during the subsequent washprocess is prevented by keeping all exposed metal surfaces wetted withthe inhibited reaction product by using a spray nozzle and arecirculation pump. The effectiveness of the inhibitor (methyl ether ofhydroquinone) is maintained by using 1-5% and preferably 2% oxygen inthe nitrogen pad. Care must be exercised not to exceed 5% oxygen sinceabove this amount there is danger of explosions.

The above compositions can be produced in a continuous flow reactor.Inhibited acrylic acid or methacrylic acid is reacted with DCPD or DCPDconcentrate in a molar ratio of 1:2 to 5:1 in the presence of 0.5-2.0weight % BF₃ catalyst based on a total amount of AA or MAA and DCPD. Thereaction temperature is controlled in the range of 100°-150° C. andpreferably 110°-130° C. with a residence time of 5 to 10 minutes. Thepressure is kept such that liquid phase is maintained, i.e. 30-100 psig.The main variables, catalyst concentration, temperature and residencetime, are interdependent and can be chosen such that complete oressentially complete DCPD conversion is obtained.

Following the addition reaction, the products are separated under vacuumin a falling film stripper into an overhead product consistingpredominantly of AA or MAA and the corresponding BF₃ complex which isrecycled, and a bottom product essentially free of acrylic acid andboron which is then water-washed 3-5 times at 50°-90° C. to give a wetproduct which is then dried to give the finished product.

The compositions prepared herein are useful to make crosslinked polymersalone or in combination with unsaturated monomers or unsaturated resins.

Examples of unsaturated monomers which are polymerizable with thepresent compositions are acrylates and haloacrylates, vinyl aromaticssuch as styrene, alpha methyl styrene, halo styrenes, vinyltoluene,divinyl benzene, and the like, allyl compounds such as diallyl phthalateor allyl alcohol, olefins such as butene and diolefins such asbutadiene, as well as halogenated olefins and vinyl cyanide.

Examples for unsaturated resins which are polymerizable with the presentcompositions are unsaturated polyester resins, vinylester resins asdescribed in U.S. Pat. Nos. 3,367,992, 3,564,074 and 3,594,247,polybutadiene and polyisoprene, styrene/butadiene copolymers and thelike.

Polymerization is accomplished by a free radical mechanism i.e. usingfree radical catalysts, including initiation by electron and ultravioletirradation.

The above thermosetting resins are blended with an ethylenicallyunsaturated monomer mixture copolymerizable with the unsaturatedpolymers. The mixture comprises vinyl aromatic monomers such as styrene,alphamethyl styrene, chlorostyrene, vinyl toluene, divinyl benzene, anddiallyl phthalate with about 5 to about 90 weight percent ofcycloaliphatic acrylate concentrate.

The thermosetting resins blends with the unsaturated monomer mixtureshould contain 20 to about 70 percent by weight and preferably 30 to 50percent by weight of the monomer mixture based on the weight of theresin. A small amount of inhibitor such as tertiary butyl catechol,hydroquinone, or the like is added to this mixture. The amount added isgenerally in the range from about 50-300 parts per million based on theamount of unsaturated monomer.

The final blend is a crosslinkable resin composition which is useful tomake laminates.

Laminates are made by mixing into the crosslinkable composition freeradical forming catalysts and adding this mixture to a suitable fibroussubstrate such as asbestos fibers, carbon fibers, fibrous glass, orinorganic fibers. Examples of these catalysts are benzoyl peroxide,tertial butyl peroxide, methylethylketone peroxide and the like. It isalso of value to add accelerators such as cobalt naphthenate, dimethylaniline, and the like.

The cross linkable composition is rolled, sprayed or impregnated intothe fibrous reinforcement such as fibrous glass and cured in a mannerwell known in the art. When fibrous glass is used, it can be in any formsuch as chopped strands, filaments, glass ribbons, glass yarns, orreinforcing mats.

The following examples are presented to illustrate but not limit theinvention.

EXAMPLE 1

Glacial acrylic acid (AA) containing 0.1% methylether of hydroquinone(MEHQ) inhibitor and borontrifluoride etherate catalyst were premixed ina stainless steel feed tank and pumped with a metering pump to a mixingtee where they were combined with a metered stream of dicyclopentadiene(DCPD) inhibited with tertiary butyl catechol. This feed mixture waspreheated and converted in a jacketed 3/8" O.D.×0.035" walls×35" lengthreactor tube made of stainless steel. The reaction temperature wasmaintained by controlling the jacket temperature. The reaction pressurewas controlled at 30-60 psig to maintain liquid phase. Steady stateconditions were reached in 15-30 minutes. The effluent from the flowreactor was fed via a let-down valve to a falling film stripper columnof 1/2" O.D.×0.035" wall×46" length. The feed was distributed to thestripper wall via a slotted weir. The stripper temperature wascontrolled with a steam heated jacket and the pressure was reduced witha vacuum pump outfitted with a pressure regulator. In the stripper,predominantly acrylic acid/BF₃ complex and acrylic acid are removedoverhead through a rectification/demister section. Overheads and bottomswere cooled and collected for mass balance and analysis.

The reactor was fed at a rate of 3.24 ml/min with a glacial acrylicacid/BF₃ etherate mixture (2.53% BF₃ etherate) and with 3.19 ml/min DCPD(96% pure DCPD). This corresponds to a 2/1 molar ratio of acrylic acidto DCPD and 0.6% BF₃ based on total feed. Temperatures in the reactorand stripper were 120° C. The pressure in the stripper was 5 mm Hg. Theresidence time in the reactor was eight minutes, and about two minutesin the stripper.

During a 2.5 hour period of continuous run, the following qunatitieswere fed and recovered:

    ______________________________________                                        Feed            Product                                                       ______________________________________                                        AA + BF.sub.3 Et.sub.2 O                                                                  903.70 g                                                                              Bottom Product                                                                            1248.98 g (72.7%)                             DCPD        823.80 g                                                                              Overhead     469.81 g (27.3%)                                                 Product                                                   Total      1727.50 g                                                                              Total       1718.79 g                                     ______________________________________                                    

706.4 of the stripper bottoms were placed in a one gallon glass bottle,stirred and heated to 70° C. 689.6 g of 70° C. deionized water wereadded and the mixture was stirred for five minutes. Excellent phaseseparations were obtained with separation times of 3 to 3.5 minutes. Thewashing was repeated three times and 689 g of wet dicyclopentadieneacrylate concentrate were obtained. This material was dried in a twoliter flask equipped with a magnetic stirring bar at room temperature at12 mm Hg. Loss was 13.65 g or 1.98% giving 675.35 g of a bright clearliquid with the following properties:

    ______________________________________                                        Gardner color          6-7                                                    Viscosity             22 cps (24° C.)                                  Boron                  2 ppm                                                  Dicyclopentadiene acrylate                                                                          83.6%                                                   (DCPDA)                                                                       Polycyclopentadienyl acrylates                                                                      12.6%                                                   Copolymers of acrylic acid                                                                           1.0%                                                   Polyacrylates          2.8%                                                   ______________________________________                                    

Similar results are obtained when the acrylic acid is replaced withmethacrylic acid.

EXAMPLE 2

Using the identical procedure and conditions, but using a DCPDconcentrate as feedstock the following results were obtained:

    ______________________________________                                        Conversions         99.7% (based on DCPD)                                     Gardner color        9-10                                                     Viscosity           63.9 cps (24° C.)                                  Dicyclopentadiene acrylate                                                                        72.7%                                                     (DCPDA)                                                                       Polycyclopentadienyl acrylates                                                                    10.2%                                                     Copolymers of acrylic acid                                                                        14.0%                                                     Polyacrylates        3.0%                                                     ______________________________________                                    

The above dicyclopentadiene concentrate contained 84% DCPD, 13% dimersof cyclopentadiene with isoprene, piperylene, etc., and 2%tricyclopentadiene and tetracyclopentadiene.

EXAMPLE 3

237.6 pounds of dicyclopentadiene (DCPD) (97% pure DCPD) were inhibitedwith 238 g of methylether of hydroquinone (MEHQ) dissolved in 900 gacrylic acid. 194.4 pounds of glacial acrylic acid containing 0.1% MEHQinhibitor were loaded into a stirred 100-gallon stainless steel reactorand mixed with 2476 g of BF₃ etherate. The empty space in the reactorwas filled with 2% O₂ in nitrogen at 2-5 parts. All exposed metalsurfaces were kept wetted with inhibited reaction mixture or by aninternal spray system. 11.0 pounds of the inhibited DCPD were added tothe kettle and the temperature increased to 40° C. After analysis showedthat the reaction had started, the DCPD was added at a rate of about 25pounds/hour (9.6 hrs) at 50°-60° C. After all DCPD was added, thereaction was completed at 70° C. in 3.2 hours. Unreacted acrylic acid,catalyst, and color bodies were removed by five washes with 50-65gallons of water at 70° C. The washed material was dried for three hoursuntil the kettle conditions were 69° C. and 33 mm Hg. The product wascooled, drummed, and the MEHQ concentration adjusted to 190 ppm. 363pounds of cycloaliphatic composition were obtained. The yield on DCPD is98.8%. The product has the following characteristics:

    ______________________________________                                        Gardner Color         3-4                                                     Viscosity            16.7 cps (at 24° C.)                              Boron                 5.6 ppm                                                 Dicyclopentadiene acrylate                                                                         87.7%                                                    (DCPDA)                                                                       Polycyclopentadienyl acrylate                                                                      11.2%                                                    Copolymers of acrylic acid                                                                          0.9%                                                    Polyacrylates         0.2%                                                    ______________________________________                                    

Control 1

An identical experiment to example 3 was performed but without oxygen inthe nitrogen pad and without an internal spray. This resulted in aproduct containing polyacrylic acid and it formed severe emulsions uponwashing with hot water which could not be broken in a coalescer.

EXAMPLE 4

Resin blends with a commercial vinyl ester resin identified as Derakane411 were prepared as follows:

    ______________________________________                                                   Wt. %                                                                         A          B     C                                                 ______________________________________                                        Derakane 411 55           55    55                                            Styrene      45           36    27                                            CAC          --            9    18                                            ______________________________________                                    

The above CAC symbols indicate a cycloaliphatic acrylate compositionhaving the following approximate analysis in percent by weight

    ______________________________________                                        Dicyclopentadiene acrylate                                                                         81.0                                                     Polycyclopentadienyl acrylate                                                                      9.3                                                      Copolymers of acrylic acid                                                                         1.0                                                      Polyacrylates        8.0                                                      ______________________________________                                    

The cure systems used for the respective resins were:

    ______________________________________                                                      Wt. %                                                                         A        B      C                                               ______________________________________                                        MEK peroxide    1.0        1.5    1.5                                         Cobalt Naphthenate 6%                                                                         0.1        0.2    0.2                                         Dimethylaniline 0.1        0.15   0.2                                         Gel time, (min.)                                                                              17.7       17.4   18.6                                        ______________________________________                                    

All resin blends were adjusted to the same gel time. The extra promoterand catalyst requirements for Samples B and C is due to higherconcentration of MEHQ (methyl ether of hydroquinone).

Glass laminates were prepared using a normal hand lay-up technique. Thefinished laminates contained 75% resin and 25% fiber glass. The monomerloss of the laminates, recorded over time, was:

                  TABLE 9                                                         ______________________________________                                                 %                                                                    Minutes    A             B     C                                              ______________________________________                                         5         --            0.9   0.6                                            10         --            2.0   1.2                                            15         2.6           2.8   1.7                                            20         --            3.5   2.3                                            25         --            3.5   2.6                                            30         4.4           --    2.6                                            45         4.8           --    --                                             60         4.8           --    --                                             ______________________________________                                    

The above data shows that the monomer loss stopped sooner with the CACsystem than the all-styrene system. The monomer loss reduction was 27%for resin B and 46% for resin C.

The hardness development rates for the respective laminates are:

    ______________________________________                                                 Barcol Hardness                                                      Time       A             B     C                                              ______________________________________                                        30      min.   --            42  15                                           1       hr.     7            43  28                                           2       hr.    14            44  35                                           4       hr.    18            43  37                                           6       hr.    21            44  39                                           8       hr.    23            43  39                                           1       day    26            44  40                                           2       days   32            44  42                                           3       days   32            46  42                                           ______________________________________                                    

The above data shows that the compositions of this invention can beeffectively used to accelerate the hardness development of vinyl esterresins.

EXAMPLE 5

The resin blends of example 4 were repeated using pure distilleddicyclopentadiene acrylate, i.e. monomer grade (MG). The results of theBarcol Hardness test is shown below comparing the results of thecycloaliphatic acrylate compositions CAS with the pure distilleddicyclopentadiene acrylate (MG).

    ______________________________________                                               Barcol Hardness                                                                     B          C                                                     Time     A         CAC    MG      CAC  MG                                     ______________________________________                                        30    min.   --        42   --      15   --                                   45    min.   --        --   30      --   16                                   1     hr.     7        43   32      28   21                                   2     hr.    14        44   --      35   --                                   4     hr.    18        43   --      37   --                                   5     hr.    --        --   33      --   29                                   ______________________________________                                    

The above data shows that the compositions of this invention wassuperior to the pure DCPA acrylate in accelerating the hardnessdevelopment of vinyl ester resins.

EXAMPLE 6

An unsaturated polyester resin was made up of 0.4 mol maleic anhydride,0.6 moles phthalic anhydride, and 1.1 mol propylene glycol was cookedfor two hours to a temperature of 140° C. The temperature was increasedto 170° C. for one hour, then it was increased to 200° C. for theremainer of the cook cycle until an acid number of 30-35 was achieved;100 ppm hydroquinone was added with the temperature of the resin at 150°C. The resin was poured out and allowed to cool to room temperature.

Resin blends were made with this general purpose polyester resin asfollows:

    ______________________________________                                                       A         B                                                    ______________________________________                                        Polyester resin  55 wt. %    55 wt. %                                         Styrene          45          33.8                                             CAC              --          11.2                                             ______________________________________                                    

The above cycloaliphatic acrylate composition (CAC) was prepared as inExample 3.

The cure systems used for the respective resins were:

    ______________________________________                                                        A     B                                                       ______________________________________                                        Cobalt Naphthanate                                                                              0.1%    0.1%                                                n,n,-Dimethylaniline                                                                            0.1     0.1                                                 p-Benzoquinone    0.048   0.026                                               MEK Peroxide      1       1                                                   Gel time (min.)   17.4    17.4                                                ______________________________________                                    

Glass laminates were prepared by using 2-ply fiber glass. The finishedlaminates contained 75% resin and 25% glass. The monomer weight loss ofthe laminates was recorded over time.

    ______________________________________                                        Time (min.)      A       B                                                    ______________________________________                                        10               3.06    2.93                                                 15               3.99    3.62                                                 20               5.26    4.74                                                 25               6.39    5.44                                                 30               7.52    6.20                                                 45               9.38    7.25                                                 60               9.58    7.25                                                 75               9.71    7.25                                                 90               9.71    7.25                                                 ______________________________________                                    

The monomer loss was decreased and the time was shortened in resin Bwhen CAC was present. The monomer loss reduction was 25% for resin B.

The Barcol hardness development rates for the respective laminates are:

    ______________________________________                                        Time (hrs.)       A      B                                                    ______________________________________                                        1                  0     11                                                   2                  6     19                                                   3                 14     25                                                   4                 23     26                                                   5                 23     28                                                   6                 26     33                                                   7                 29     33                                                   8                 30     36                                                   24                35     40                                                   ______________________________________                                    

The above data shows that the composition of this invention can beeffectively used to accelerate the hardness development of generalpurpose polyester resins.

EXAMPLE 7

A commercially available ultraviolet light curable vinyl ester resin(Bis phenol A-Epoxy-Acrylic resin) was blended with an equal weight ofthe CAC used in Example 4. As a photoinitiator, 3% by weight ofdiethoxyacetophenone was blended into the mixture. The sample was coatedon a steel panel and passed under a 200 watt per linear inch ultravioletlamp at a fixed speed of 100 feet per minute. After about 15 passes, ahard mar-free coating was obtained.

We claim:
 1. A thermosetting resin composition which comprises:(1) anunsaturated polyester resin, and (2) an unsaturated monomer mixture of avinyl aromatic monomer and a cycloaliphatic acrylate compositioncomprising (A) about 60 to 95 percent by weight of dicyclopentadieneacrylate, methacrylate, or mixtures thereof (B) about 2 to 15 percent byweight of a mixture of polycyclopentadienyl acrylates of the formula##STR8## where R is CH₂ ═CZ--C(O)--O-- Z is H, or methyl n is 1, or 2 mis 0 or 1 and when m is 0 there is a double bond present (C) about 1 toabout 21 percent by weight of a mixture of the copolymers of methacrylicacid or acrylic acid with adducts of cyclopentadiene with isoprene,piperylene, or mixtures thereof, (D) about 0.05 to about 10 percent byweight of a mixture of poly acrylates having the repeating unit ##STR9##where R¹ is hydrogen or ##STR10## R² is CH₂ ═CZ--C(O)--O-- Z is H ormethyl n is 0, 1 or 2, and m is 0 or 1 and when m is 0 there is a doublebond present.
 2. A cured fibrous laminate made with the composition ofclaim 1.